AlGaAs VSCELs grown on thin 150 mm germanium substrates

Gillgrass, S. J., Baker, J., Allford, C. P. ORCID: https://orcid.org/0000-0002-3798-9014, Davies, J. I., Shutts, S. ORCID: https://orcid.org/0000-0001-6751-7790 and Smowton, P. M. ORCID: https://orcid.org/0000-0002-9105-4842 2025. AlGaAs VSCELs grown on thin 150 mm germanium substrates. JPhys: Photonics 7 (3) , 035033. 10.1088/2515-7647/adef1f

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Abstract

To reduce material usage and minimise device cost the use of reduced substrate thickness is considered in high volume vertical-cavity surface-emitting laser (VCSEL) manufacturing. For large-diameter VCSEL wafers, germanium (Ge) is emerging as an alternative substrate solution. In this work, VCSEL structures designed for 940 nm emission are grown by metal–organic vapour-phase epitaxy on 150 mm (6 inch) germanium substrates of thickness 675, 450 and 225 µm. Using on-wafer testing of fabricated devices, threshold current density, differential resistance, and emission wavelength are compared across the three substrate thicknesses, with results demonstrated for the first time on a Ge wafer thickness of 225 µm. These results underline the potential of thin Ge substrates for reduced material usage in VCSEL manufacturing.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Schools > Physics and Astronomy
Additional Information:	License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Type: cc-by
Publisher:	IOP Publishing
Funders:	Engineering and Physical Sciences Research Council
Projects:	EP/Z532848/1, EP/P030556/1
Date of First Compliant Deposit:	4 August 2025
Date of Acceptance:	13 July 2025
Last Modified:	02 Aug 2026 15:06
URI:	https://orca.cardiff.ac.uk/id/eprint/180229

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